NZ dolphin survival boosted by Marine Protected Area

Hector's dolphin (c) S Dawson

Related Stories

Hector's dolphins living off the coast of Christchurch, New Zealand have benefitted from the area's special designation, say scientists.

Researchers studied the animals, one of the world's most endangered species of dolphin, for 21 years.

Their results show that the survival rate of the dolphins has increased by 5.4% since the Marine Protection Area (MPA) was declared.

The findings are published in the Journal of Applied Ecology.

"This is the first evidence that Marine Protected Areas can be effective for marine mammals. We found a significant improvement in the survival rate," said Dr Liz Slooten from the University of Otago who undertook the research.

In 1988 the Banks Peninsula Marine Mammal Sanctuary was established in the hope that resident dolphins would be protected from fatalities associated with the gillnet and trawling activities of the fishing industry.

A team of ecologists conducted regular photo identification of the dolphins for 21 years, starting two years before the area was officially protected.

Start Quote

The MPA hasn't quite yet 'saved' the dolphins but it's been a major step in the right direction. ”

End Quote Dr Liz Slooten University of Otago, New Zealand

"We can identify individual dolphins from their battle scars - which range from small nicks out of the dorsal fin to major scarring following shark attacks," explained Dr Slooten.

The researchers used the photographs to create a population model; with this they were able to analyse how the animals had fared over two decades.

"Estimating population changes in marine mammals is challenging, often requiring many years of research to produce data accurate enough to detect these kinds of biological changes," said Dr Slooten.

"It seems to take a long time for a dolphin population to respond to protection, and therefore a long-term study to detect [any] improvement."

'Not safe yet'

The teams models suggested that the dolphins' survival rate had increased by 5.4% - a positive result but not what the team had expected.

"At first, we were surprised that the survival rates had not increased further," said Dr Slooten, "Once the Banks Peninsula area was protected, we had expected the problem to be solved and the population to be healthy and recovering."

Hector's dolphins (c) Steve Dawson
  • Hector's dolphins are one of the world's smallest species, reaching up to 1.5m long
  • They have a characteristic black dorsal fin, which, researchers have noted, resembles Mickey Mouse's ear
  • Fewer than 7,500 animals remain in the wild

The team found that the dolphins did not spend the whole year in the protected area, which reached four nautical miles offshore.

In the winter, more than half the dolphins were found up to 16 nautical miles outside of the MPA.

"The dolphins don't care how far offshore they are, their distribution relates to water depth," Dr Slooten explained.

The New Zealand government is now considering whether to extend MPAs where Hector's dolphins are found.

"The good news is that the situation has improved. The population was doing a nose-dive, declining at 6% per year, and now it's only declining slowly [at] about 1% per year," said Dr Slooten.

"The bad news is that the protected area is still too small. It would need to be extended further offshore to allow the population to stop declining and better still to grow and recover towards its original population size."

"The MPA hasn't quite yet 'saved' the dolphins but it's been a major step in the right direction."

More on This Story

Related Stories

The BBC is not responsible for the content of external Internet sites

More from nature

  • Cardinal fish and ostracodFish filmed spitting 'fireworks'

    Film crew captures ostracods' spectacular defensive lightshow that makes predatory fish spit them out.

  • Arapaima'Locally extinct'

    A giant fish which used to dominate the Amazon river is now absent in many areas

  • DragonflyRapid reactions

    Dragonfly's super quick reactions recorded in slow motion by BBC film-makers

  • Wingless adult male of the midge Belgica antarcticaExtreme survivor

    Antarctic midge's small genome may be an adaptation to its extreme environment

  • Myotis midastactus specimen (previously identified as Myotis simus)Golden discovery

    A bat from Bolivia is described as a new species by scientists

  • Dinosaurs 'shrank' to become birds

    Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, new research shows.

  • Would we starve without bees?

    Honey bees are under threat, and as pollination significantly contributes to the food we eat, what would we do without them?

  • Eggshells may act like 'sunblock'

    Birds' eggs show adaptations in pigment concentration and thickness to allow the right amount of sun for embryos, scientists say.

  • Female shrimps are more aggressive

    Female snapping shrimps are more aggressive than males when defending their territories despite their smaller claw size, a study shows.

BBC iWonder

  • Honey bee close-upInsect intelligence

    Are honey bees as smart as your sat nav?

  • Tyrannosaurus rex skull (c) Mark Williamson / Science Photo LibraryDinosaur dynasty

    One group of dinosaurs survived and their descendants can be seen all around us today

  • Brown rat cluse upRise of the rodent

    Reports of giant, 'super rats' are filling the headlines. But why are we being overrun by rats?

  • Cuckoo portraitHoliday hotspot

    What makes the UK such an attractive destination for visiting wildlife?

Awesome! And there's nothing common about such beauty.

Elaine Bernon on Facebook comments on the trio of common blue butterflies in our Photo of the Day.

Things To Do


More Nature Activities >

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.